SCR脱硝过程中SO_2催化氧化的原位红外研究

FT-IR study of the catalytic oxidation of SO_2 during the process of selective catalytic reduction of NO with NH_3 over commercial catalysts

采用工业用V2O5-WO3/Ti O2催化剂,基于傅里叶原位红外光谱(FT-IR)技术考察SO2的氧化过程及烟气组分对SO2氧化行为的影响;结果表明,SO2在催化剂表面氧化主要是首先吸附在催化剂表面V2O5活性位上,占据其O原子,以SO2-3形式存在,后与催化剂表面V5+-OH发生反应,生成金属硫酸盐(VOSO4)中间产物,O2重新氧化催化氧化过程中由于被SO2夺取O原子而被还原的V2O5物种,使V4+转化为V5+,促进金属硫酸盐(VOSO4)向SO3转化;SO2与NO、NH3的竞争吸附阻碍SO2在V2O5活性点位上的氧化;在SCR中,NO的脱除与SO2的氧化是相互抑制的关系。

This work briefly reveals the process of catalytic oxidation of SO2 and the influences of NH3,NO and O2 on the oxidation behavior based on FT-IR. It suggests that the process of oxidation of SO2： the absorption of SO2 on V2O5sites occupying its O atom in the form of SO3^2-; reaction between absorbed SO2 and O atom in V^5＋- OH to form an VOSO4-like structure; reoxidation of V^4＋to V^5＋by O2,promoting the transformation from VOSO4-like intermediate to SO3 and V2O5. NH3 and NO competitively absorb with SO2,suppressing its oxidation behavior. The removal of NOxand the oxidation of SO2 is the relationship of mutual inhibition.